A wide variety of door hinges are used in the electronics industry for pivotally connecting a door or panel to the front of a cabinet, housing or other enclosure structure for electronic equipment such as computer hardware. Typically, such door hinges include a first part or component which is attached to the back surface of the door, often by fasteners or adhesives, and a second part or component which is attached to a base structure, framework or inner wall of the enclosure or housing. The first and second parts are hinged together and mount the panel or door to the cabinet or enclosure. Mounting conventional hinge assemblies to plastic electronic cabinetry, however, can be tedious and add undesirably to the cost.
Snap-fitting or snap-on panels, of course, are broadly known in connection with electronic apparatus housings. Thus, resilient plastic fingers have been used to latch panels to plastic housings. Such systems, however, have most typically been employed in applications in which the panel does not need to rotate. Thus, resilient or snap-on fingers have been widely used to secure a cabinet panel in place in a fixed position, and removal of the panel is accomplished merely by prying the panel away from the structure to which it is mounted, or urging the resilient fingers out of engagement with the shoulders which they latch against to release the panel.
When a panel or door is to be rotatably or hingedly mounted to a structure, the problems attendant to such a mounting become more difficult. The hinge must accommodate rotation of the panel and yet it must securely mount the panel or door to the structure for the full range of motion of the door.
Plastic snap-fit door hinge components may be monolithically formed with the plastic housing and door pieces which are to be hinged together, namely, one part of the hinge can be provided on the cabinet and the other part of the hinge provided on the door. Such hinge assemblies, however, need an over-travel stop that limits door pivoting when the door is fully opened. Thus, a stop surface on the body of the door will engage an end stop structure on the housing to which it is mounted to prevent further rotation of the door. Such over-travel stops, however, also can produce reaction forces tending to pry the hinge components apart and thereby pry the door off the cabinet or enclosure. Thus, in the open position, the weight of the door and/or the force used to open the door can easily result in the door hinge becoming pried apart by the over-travel stop, such that the door unsnaps from the cabinet or enclosure.
To counteract the problem of a snap-fit hinge becoming easily pried apart when the door is fully opened, it is possible to design the resilient snap-fit connection between the two parts of the hinge to be quite stiff or strong. The disadvantage of this approach is that, if the snap-fit connection is designed with little resiliency, thereby securely holding the hinge together even at the door's fully opened position, it correspondingly becomes difficult to easily snap together the hinge parts when the door and cabinet are first being assembled. Moreover, it is also correspondingly difficult to easily snap apart the hinge should this be desired.
What is instead desired is a hinge assembly which easily snaps together and apart allowing a door to be easily installed or removed from the front of an enclosure, but which also does not simply snap apart when the door reaches its fully opened position.
Accordingly, it is an object of the present invention to provide a snap-fit door hinge assembly, and method for forming such an assembly, which will not become accidentally pried apart at any point over the full range of door motion, including when the door is in its fully opened position.
It is another object to provide a plastic snap-fit door hinge assembly having parts which are easily snapped together into a secure, interlocked relationship that will enable a full range of door motion.
It is another object to provide a plastic snap-fit door hinge assembly which can easily be snapped apart, allowing for easy removal of the door from the structural member to which it is mounted.
It is another object to provide a plastic snap-fit door hinge which can be easily assembled together, is inexpensive to construct, is suitable for formation using convention plastic forming techniques, requires little or no maintenance and is durable.